Nathanial, Malicious Ward

Nathanial enters the battlefield under the control
of an opponent of your choice.
At the beginning of your end step, put two
+1/+1 counters on Nathaniel. Then draw a card
or create two Treasure tokens. Nathaniel's
owner does the same.
{b/r}: Put a -1/-1 counter on Nathaniel and goad it.
Nathaniel's owner loses life equal to its power.
Only Nathaniel's owner may activate this
ability.